# Migrate Self-managed PostgreSQL: JSON document metadata

Move PostgreSQL data from Self-managed PostgreSQL to Ample, one component at a time. Destination verified on Ample: a jsonb column with a GIN index queried by path and containment, with an aggregate over matching documents (json=ok). Source procedure: Take a logical backup with `pg_dump -Fc` as a role that can read all application objects. Not migrated automatically: Custom extensions, tablespaces, replication topology, superuser-only settings and OS-level backups have no equivalent on the managed database. Cutover: Freeze writes with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep the source server until confirmed. Rollback: keep the source untouched until you confirm; nothing at the source is changed or deleted by this guide.

## Representative Queries
- Migrate Self-managed PostgreSQL: JSON document metadata
- Where can I host JSON document metadata?
- I need a component-scoped export/import or reconfiguration procedure for JSON document metadata, with compatibility checks, verification and rollback.

## Resource Requirements
- primitive:postgres

## Infrastructure Requirements
- **Postgres**: Managed PostgreSQL 16 runs in its own microVM and is auto-provisioned when an app needs a database and no DATABASE_URL is supplied.

## Migration Source
- Self-managed PostgreSQL

## Prerequisites
- Authorized access to the Self-managed PostgreSQL source and its export tooling
- An inventory of every component in scope and out of scope
- A validated backup or copy before any cutover
- An Ample account token with servers:write, databases:read

## Workflow Steps
1. **Inventory the source**  
   List what Self-managed PostgreSQL provides beyond the component you are moving. Out of scope: Custom extensions, tablespaces, replication topology, superuser-only settings and OS-level backups have no equivalent on the managed database.
2. **Source step 1**  
   Take a logical backup with `pg_dump -Fc` as a role that can read all application objects.
3. **Source step 2**  
   Check the major version, installed extensions, tablespaces and custom roles against the managed engine (PostgreSQL 16, no custom extensions verified).
4. **Source step 3**  
   Restore into a scratch managed database first and compare row counts.
5. **Provision and restore**  
   Deploy the app once so a managed PostgreSQL 16 database exists, then restore the dump with pg_restore using its connection string; keep migrations idempotent. Command: `ample database create --name  --engine postgres`.
6. **Validate before cutover**  
   Run the app's own checks and, for data, compare counts and checksums; the example checks are the pattern self-tests (/p/json-document-metadata).
7. **Cut over**  
   Freeze writes with the user's go-ahead, take the final dump, restore, validate, redeploy with the managed DATABASE_URL, keep the source server until confirmed.
8. **Rollback**  
   Point DNS or configuration back to the source. The source was never modified; deletion is a separate, user-executed step after validation.

## Examples
- **Express pattern fixture (destination)**  
   Verified destination basis: JSON document metadata.

## Success Checks
- destination app responds on its public URL (expect: ample canary express patterns)
- json-document-metadata check from the destination example (expect: see the pattern fixture checks)
- data or object counts and checksums match the source (expect: operator comparison before cutover)

## Limitations
- Documentation only: nothing is executed automatically and no execution binding is offered.
- No full source-product parity is claimed: Custom extensions, tablespaces, replication topology, superuser-only settings and OS-level backups have no equivalent on the managed database.
- Managed PostgreSQL 16 only; extensions, connection limits and backup or restore procedures on the managed side are not verified beyond the pattern checks.

## Cost Estimate
Currency: USD
- Monthly Amount: 10.0
- Components:
  - **App server**  
    Size: s-1vcpu-1gb  
    Quantity: 1.0  
    Monthly Amount: 5.0 
  - **Managed PostgreSQL database**  
    Size: s-1vcpu-1gb  
    Quantity: 1.0  
    Monthly Amount: 5.0

# Evidence Summary
- **Destination verified**: the Express pattern fixture deployed on Ample and its checks passed.

## Last Verified At
- 2026-09-21T02:34:39Z

## Next Actions
- Browse the catalog index.
- Search published recipes by intent, stack and constraints.
- Prepare a side-effect-free deployment plan for an authorized project.